Patent GB-644864-A (GB)
Title: Automatic position plotter
IPC: G01C21/22
Filed: 1946-12-31
Abstract: 644,864. Calculating-apparatus. BENDIX AVIATION CORPORATION. Dec. 31, 1946, No. 38161. Convention date, Jan. 23. [Class 106 (i)] [Also in Groups XX and XL (c)] In a course-recording apparatus an electrical computer is provided which supplies voltages proportional to the co-ordinates X, Y of the craft from inputs proportional to the bearings ex, # of the craft from two wireless transmitting stations having co-ordinates X1, Y1 and X2, Y2 respectively or from inputs proportional to the bearing a and the range d of the craft from a single transmitter having co-ordinates X1, Y1. The signals from two automatic direction-finders fitted to the craft having been combined with the suitably corrected output of a magnetic or flux-gate compass so as to be proportional to the tone bearings α, # are amplified and fed to torque amplifiers 52, 54, Fig. 4, respectively which drive shafts 56, 58. Shaft 56 drives the rotors of resolvers 68, 70 whose outputs are proportional to sin α, cos a respectively and also the rotors of resolvers 72, 74, 76, 78 whose stators are positioned by a cylinder 66 driven by the shaft 58 so that their outputs are all proportional to sin (α-#). Shaft 58 also drives the rotor of a resolver 60 which has two outputs, proportional to sin # and cos # respectively. The stator windings 69, 73, 77, 81, 84, 86, Fig. 5, of resolvers 68, 70, 72, 74, 76, 78, are supplied with current from tappings of potentiometers 35, 37, 39, 41, 30 and 38 so that their rotor outputs are proportional to (X2 - X1) cos α, (Y1 - Y2) sin α, X2 sin (α - #), Y2 sin (α - #), - X sin (α - #), - Y sin (α - #) respectively. The potentiometers are supplied with current at 100 volts 400 cycles and the tappings of potentiometers 35, 37, 39, 41 are adjusted manually to the co-ordinates X1, X2, Y2, Y1 respectively. Potentiometers 30, 38 are tapped by sliding contacts operated by the lead-screws of the X and Y motors 24, 26 of the recording apparatus, the tappings being adjusted automatically in correspondence with the position of the recording-pen. The combined outputs of resolvers 68, 70 are fed to the stator 88 of the resolver 60 and the cosine output from its rotor 90 is added algebraically to the output of resolvers 74 and 78 to give a voltage proportional to - Y sin (α - #) + Y2 sin (α-#)+[(X2- X1) cos α+(Y1 - Y2) sin α] cos # and the sine input from its rotor 89 is added to the output of resolvers 72, 76 to give a voltage proportional to -X (sin α - #)+X2 sin (α - #)+ [(X2 - X1) cos α+(Y1 - Y2) sin α] sin #. These output voltages are amplified in amplifiers 20, 21 and fed to the X and Y motors 24, 26 driving the pen of the recording apparatus (see Group XX). The drive is maintained until the pen is in correspondence with the position of the craft whereat the voltages X, Y set up in the potentiometers 30, 38 are at the correct values to equate the outputs of the rotors 89, 90. of the resolver 60 to zero. In a modification, where the position is plotted from the range d and the bearing a of a single transmitter having co-ordinates X1, Y1, the rotor 118, Fig. 8, of a resolver 116 is positioned in accordance with the angle a and is supplied with a voltage proportional to d from a potentiometer 112. The resolver 116 has two stator windings 120, 122 cosine and sine wound and supplied with voltages proportional to X1 - X and Y1 - Y respectively from tappings of potentiometers 35, 30, 41, 38 through transformers 115 and 121. The voltage outputs of the windings 120, 122 are therefore proportional to Y1 - Y+ d cos x and X1 - X+d sin α respectively and are applied to drive the X and Y motors of the recording apparatus until the sliding contacts 34, 44 on the potentiometers 30, 38 are so positioned that these voltages are equated to zero whereby the recording pen will be in a position corresponding to that of the craft.